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Bio 3 Reproduction
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| Question | Answer |
|---|---|
| What are the phases of the cell cycle? | Interphase (G1, S, G2) and M phase |
| What happens in G1 phase? | During G1 phase, aka the Presynthetic Gap, cells create organelles for energy and protein production. |
| What happens in S phase? | Synthesis: cells replicate the genetic material so that there are 2 sister chromatids joined at the centromere. Ploidy does not change ---- there are still 46 chromosomes, but 92 chromatids. |
| What happens in G2 phase? | The post-synthetic gap is for quality control. |
| What is M phase? | Mitosis and cytokinesis, when the cell divides. |
| In what form are chromosomes during interphase? | Chromosomes are in chromatin form, i.e. less condense. |
| What are centrioles? | Organelles kept in the centrosome (an area outside the nucleus) that are responsible for chromosome movement. They move to opposite poles during prophase and form spindle fibers made of microtubules. |
| What are asters? | The points where chromosomes attach to spindle fibers. |
| What are the stages of mitosis? | prophase, metaphase, anaphase, telophase, and cytokinesis. |
| What happens during prophase? | Chromosomes condense, centrioles move to poles and the spindle apparatus forms. The nuclear membrane and nucleoli disappear. Kinetochores, with attached kinetochore fibers, appear at the chromosome centromere. |
| What happens during metaphase? | Kinetochore fibers interact with the spindle to align chromosomes at the metaphase plate. |
| What happens during anaphase? | Centromeres split so each chromatid is separate, then they're pulled to opposite poles by the shortening of kinetochore fibers. |
| What happens during telophase? | The spindle apparatus disappears, nuclear membrane and nucleoli reform, and the chromosomes uncoil. |
| What happens during cytokinesis? | The cell divides, splitting the cytoplasm and organelles so that each daughter cell has what it needs to survive. |
| What are the types of asexual reproduction? | Binary fission, budding, Regeneration, and Parthogenesis |
| What is parthogenesis? | A type of asexual reproduction where an adult develops from an unfertilized egg. |
| What is meiosis? | 1 round of replication and 2 rounds of division that produce gametes, sex cells. |
| What is meiosis I? | Reductional division that results in homologous chromosomes separating and generating haploid daughter cells. |
| What is meiosis II? | Equational division, similar to mitosis, separates sister chromatids and gives 4 unique haploid cells. |
| What happens in prophase I? | The duplicated chromatin condenses, spindle apparatus forms, nucleoli and nuclear membrane disappears, homologous chromosomes intertwine (synapsis) resulting in a tetrad of 4 chromatids which cross over. |
| What happens in metaphase I? | Tetrads align at the equatorial plane, each pair attaches to a separate spindle fiber by its kinetochore. |
| What happens in anaphase I? | homologous pairs separate (called disjunction). |
| What happens in telophase I? | The nuclear membrane forms, and cells divide by cytokinesis into 2 daughter cells. These cells are haploid, but each chromosome still has its sister chromatids. |
| What happens in prophase II? | Centrioles move to the poles and the spindle forms. |
| What happens in metaphase II? | The chromosomes align, centromeres divide, and centromeres split. |
| What happens in anaphase II? | The sister chromatids are pulled to the poles by the spindle fibers. |
| What happens in telophase II? | The nuclear membranes form and and the cells divide into 2 haploid cells. |
| What are the 2 functional components of the testes? | Seminiferous tubules - where sperm are made and nourished by Sertoli cells. Interstitial cells (cells of Lydig) - secrete testosterone and other hormones, androgens |
| What is the epididymis? | Where the sperm mature, which takes about 72 days. The sperm gain motility in the form of a flagellum. |
| Where does the sperm go during ejaculation? | It moves through the ejaculatory duct and urethra, exits through the penis. |
| What makes seminal fluid? | The seminal vesicles, prostate gland and bulbourethral gland. |
| What is the sperm pathway? | SEVEN UP : Seminiferous tubules, Epididymis, Vas Deferens, Ejaculatory Duct, nothing, Urethra, Penis |
| What is spermatogenesis and where does it occur? | It forms sperm through meiosis and occurs in the seminiferous tubules? |
| What are spermatogonia? | diploid stem cells which replicate their genetic material and develop into diploid primary spermatocytes |
| What is the product of Meiosis I? | haploid secondary spermatocytes |
| What is the product of meiosis II? | haploid spermatids which turn to spermatozoa |
| What is an acrosome? | The cap of a sperm, which is needed to penetrate the ovum |
| What are the female gonads? | Ovaries which consist of thousands of follicles, multilayered sacs that contain immature ova |
| What hormones do the ovaries produce? | estrogen and progesterone |
| Where does the egg go once per month? | Into the peritoneal sac which lines the abdominal cavity then into the fallopian tube or oviduct (lined with cilia) |
| Describe the beginning of oogenesis. | All oogenia are formed during fetal development and at birth, we have predifferentiated cells called primary oocytes (2n), stuck in prophase I. |
| What happens to oocytes after menarche? | 1 primary oocyte per month will complete meiosis I, which creates a secondary oocyte and a polar body. The secondary oocyte is frozen in metaphase II until fertilized. |
| When does meiosis II for oogenesis occur? | It happens when sperm, using acrosomal enzymes, penetrates 2 cell layers around the oocytes (zona pellucida and corona radiata) |
| What are the products of meiosis II? | mature ovum and polar body |
| What happens after menopause? | The ovaries are less sensitive to hormones FSH (follicle stimulating) and LH (luteinizing) and eventually atrophy. |
| What happens to hormone levels after menopause? | FSH and LH levels shoot up because there is no estrogen and progesterone feedback. |
| When can secondary oocytes be fertilized? | within 24 hours of ovulation |
| What are acrosomal enzymes? | Digest the corona radiata and penetrate the zona pellucida of the ovum |
| What happens at fertilization? | At contact with the membrane, the sperm forms a tubelike acrosomal apparatus which extends and penetrates the membrane. Then the nucleus can enter the ovum which undergoes a cortical reaction. |
| What is the cortical reaction of fertilization? | Calcium ions, which increase metabolic rate, are released to the cytoplasm which leads to formation of the fertilization membrane, impenetrable to other sperm |
| How are monozygotic twins formed? | when a single zygote splits |
| How are dizygotic twins formed? | when 2 eggs are released in the same cycle and both are implanted on the uterine wall |
Created by:
schoe
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